Production of chenodeoxycholic acid

ABSTRACT

THIS INVENTION RELATES TO NOVEL METHODS OF SYNTHESIZING 3A,7A-DIHYDROXY-5B-CHOLANIC ACID AND NOVEL INTERMEDIATES THEREFOR.

United States Patent 3,833,620 PRODUCTION OF CHENODEOXYCHOLIC ACID William H. Saltzman, New Rochelle, N.Y., assignor to Intellectual Property Development Corporation, New Rochelle, N.Y. No Drawing. Filed Nov. 16, 1972, Ser. No. 307,060

Int. Cl. C07c 169/48 US. Cl. 260-3971 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to novel methods of synthesizing 3a,7a-dihYdI'OXY-5fl-Ch0ltlni0 acid and novel intermediates therefor.

This invention relates to and has for its object the synthesis of 3a,7a dihydroxy-5B-cholanic acid and to novel intermediates therefor. The final compounds of this invention are known and have been found to possess useful biological properties.

A novel method has been discovered for the production of 3a,7a-dihydroxy-5fi-cholanic acid which entails a number of steps beginning with 3a,7a,l2a-trihydroxy- Sfl-cholanic acid or analogs thereof as starting material. More particularly, this invention involves the method of producing 3a,7a-dehydroxy-5fi-cholanic acid directly from 3a,7a,l2a-trihydroxy-5fl-cholanic acid or analogs thereof and is more clearly illustrated by the following chemical equations wherein R, Z, Y and X are as defined in the respective formulae below:

CODE

3,833,620 Patented Sept. 3, 1974 or acyl anhydride, for example acetic anhydride, respectively, to yield the respective 12a-sulfonated esters, compounds B, which are new compounds of this invention. Compounds B are then desulfohydrated as by treatment with a suitable desulfohydration agent, for example potassium t.-but0xide combined with dimethyl sulfoxide to yield the ll-ene compounds, compounds C.

Alternatively, it has been found that it is possible to obtain the ll-ene compounds (Compounds C), directly from the 3,7,12-triol compounds (Compounds A) by tre'ating Compounds A with a strong dehydration agent. The dehydration agents which have been found to be suitable in the practice of this invention include such dehydration agents as, methane sulfonyl chloride, thionyl chloride or methyl chlorosulfite in the presence of an organic base, for example, pyridine. By this method, it has been possible to obtain the ll-ene compounds (Compounds C) directly from the trial compounds (compounds A).

The final 31!,7oz-di0l compounds (Compounds D), are then obtained by the catalytic hydrogenation of the 11- ene compounds (Compounds C), for example, hydrogenation in acetic acid in the presence of a palladium over charcoal catalyst.

The preferred acyl or acyloxy radicals of this invention are those of hydrocarbon car boxylic acids of twelve carbon atoms or less and include such acids as the lower alkanoic acids, the lower alkenoic acids, the cycloalkenoic acids, the aryl carboxylic acids, and other like hydrocarbon carboxylic acids.

The preferred alkyl radicals of this invention are those of six or less carbon atoms and may be characterized by the term, lower alkyl. Thus, as employed herein, lower alkyl is meant to include such moieties as methyl, ethyl, propyl, t.-butyl, pentyl and the like.

The invention may be further illustrated by the following examples.

EXAMPLE 1 Methyl 3u,7a-diacetoxy-5B-chol-l1-en-3a,7a-diol-24-oic acid Methyl 301,7 diacetoxy-S-fi-cholan-3a,7a,12a-triol-24 oic acid, prepared in accordance with the procedure set forth by Feiser, et al. in Vol. 72, J. Amer. Chem. Soc., page 5530 (1950), in pyridine is treated with p-toluenesulfonyl chloride and held at room temperature overnight. To the reaction mixture is added ice water and the resultant product is extracted with methanol, washed and dried to yield the 12oz -tosyloxy analog of methyl 3a,7a-diacetoxy-5B-cholan-3a,7a,12u-triol-24-oic acid.

The IZm-tOSYlOXY product is then treated with potassium-t-butoxide in dimethylsulfoxide at an elevated temperature, and the resultant product cooled in an ice bath, and extracted with methanol to yield methyl 3a,7a-diacetoxy-Sfl-chol-l1-en-3a,7u-diol-24-oic acid.

EXAMPLE 2 Methyl 3a,7a-diacetoxy-5p-chol-ll-en- 3u,7u-diol-24-oic acid Methyl 3a,7a-diacetoxy-Sfl-cholan-3a,7a,l2a-triol-24-oic acid is treated with dimethyl sulfoxide and acetic anhydride at room temperature for 18 hours. To the mixture is then added ice water and the resultant product extracted with methanol to yield the l2m-dimethylsulfonyl analog of methyl 3u,7a diacetoxy-Sfl-cholan-Sa,7a,l2a-triol-24-oic acid.

The 12u-dimethyl sulfonyl analog is then treated with a combination of potassium-t-butoxide in dimethyl-sulfoxide at elevated temperature, and after cooling there is obtained methyl 3a,7a-diacetoxy-5p-chol-11-en-3u,7a-diol- 24-oic acid.

3 EXAMPLE 3.

Methyl 3a,7a-diacetoxy-5{3-chol-11-en- 3a,7a-diol-24-oic acid To a solution of methyl-3a,7a-diacetoxy-5fl-cholan-3a, 7m,IZa-tIiOl-24-Oic acid in dimethylformamide is added pyridine and methanesulfonyl chloride and the mixture held overnight at room temperature. Water is added and the reaction mixture extracted with ethyl acetate. The ethyl acetate layer is washed with water, dried with magnesiurn sulfate and evaporated. Recrystallization of the crude product from ethyl acetate-hexane yields methyl 3a,7a-diacetoxy-Sfi-chol-l1-en-3 a,7u-diol-24-oic acid.

EXAMPLE 4 The procedure of Example 3 is followed except that an equivalent amount of methyl chlorosulfite is substituted for methanesulfonyl chloride, to yield the methyl 311,7- diacetoxy-Sfi-chol-l 1-611-30c,7oc-di0124-0i6 acid.

EXAMPLE 5 Methyl BaJa-diacetQXy-SB-chQl-1l-en- 3a,7a-diol-24-oic acid To a solution of methyl 3a,7a-diacetoxy-Sfi-cholan- 3u,7a,12a-triol-24-oic acid in pyridine was added thionyl chloride and the mixture held at room temperature overnight. The reaction mixture was then poured into iced water and the resultant precipitate collected, washed and dried. The resultant material was then recrystallized from methanol to yield methyl 3a,7a-diacetoxy-5/3-chol-1l-en- 3a,7a-diol-24-oic acid.

EXAMPLE 6 Methyl 3u,7u-diacetoxy-5 8-cholan- 3a,7a-(liOl-24-Dl0 acid CODE wherein R is hydrogen or lower alltyl; each Z is hydrogen or acyl; and X is CHgSCHg.

4 2. The compound of Claim 1, wherein R is methyl, and each Z is acetyl and X is CH SCH 3. The method of producing a compound of the formula 2 o-- o z wherein Z and R are as defined in Claim 1, which comprises:

(a) treating a compound of the formula:

wherein Z and R are as defined in Claim 1, with the sulfonated reagent, dimethyl sulfoxide, in the presence of a base to yield the l2a-sulfonated compound of Claim 1;

(b) dehydrating said 12a-sulfonated compound of step (a) above, by treatment with potassium-t.-butoxide in dimethyl sulfoxide to yield the ll-ene compound of the formula:

wherein Z and R are as defined in Claim 1; and (c) hydrogenating said ll-ene compound to yield the desired final product.

References Cited UNITED STATES PATENTS 1/1965 Bharucha 260397.1 6/ 1967 Bharucha et al. 260239.55

OTHER REFERENCES Kirk-Steroid Reaction Mechanisms (1968), pp. 81-84. Dferassi, Steroid Reactions, p. 239 (1963).

HENRY A. FRENCH, Primary Examiner U.S. Cl. X.R. 260--999 

